Telephone system



May 12, 719361. J. H. voss TELEPHONE SYSTEM Filed Nov. 19, 1954 HIGH PITCH 'I {RBI 92 v I l l l l I l l I -J REMAINS IN POSITION MECH. INTERLOCKED LAST OPERATED T0 WITH SW. HOOK SB I INVENTOR.

JOHN H.VOSS

' ATTORNE Patented May 12, 1936 UNITED STATES PATENT OFFICE TELEPHONE SYSTEM Application November 19, 1934, Serial No. 753,603

Claims.

This invention relates in general to telephone systems but more particularly to substation instruments and circuits, and the main object briefly stated is the provision of an improved substation instrument and circuits with which it is possible to communicate over either one of two lines connected thereto.

Telephone instruments of the above type have been provided with a number of push-buttons or keys for performing the various switching operations, one of the keys being used for talking over one line, a second key for talking over another line, and a third key for establishing a holding circuit over a particular one of said lines. In some instances all of the operated keys were restored in response to the replacement of the receiver or the keys were all manually restored in case no automatic restoring arrangement was provided. In addition, in other instances the operation of a second key automatically restored the first actuated key and in other cases the line connecting key, where a single key controls the connection of more than one line to the substation circuit, is locked against operation until the receiver is removed thereby temporarily connecting the substation circuit to one of the lines at the instant the receiver is removed when a connection with the other line is desired.

It is the object of the invention to provide a telephone instrument and circuits such that a single line connecting key is operable independent of the switchhook to connect either one of two lines to the substation circuit and two holding keys, which close holding circuits for the two lines, are only operable at will when the receiver is removed and which holding keys are automatically restored upon the replacement of the receiver. This arrangement overcomes a number of objections found in the previously mentioned types.

A feature of the invention relates to an improved holding circuit for both lines, each line having a holding bridge including the impedance of only one of the ringer coils of such lines.

Other objects and features of the invention will be apparent from the following description.

In the drawing Fig. 1 shows the schematic circuits for connecting two lines to a single substation circuit; Fig. 2 is a side View of one of the lever type keys and the switchhook controlled operating member; and Fig. 3 shows a partial rear view of the keys and spring actuating mechanism.

The substation instrument comprises a wellknown cradle-type telephone set having a subbase for mounting the key levers and associated mechanism. S indicates the circuit of the cradletype substation circuit, while the dotted line SB indicates the sub-base containing the switching mechanism diagrammatically represented there- 5 in. Two lines, line #I and line #2, shown to the right in Fig. 1 may be two local lines, a local line and a trunk line, or two trunk lines extending to an automatic telephone exchange.

The mechanism in this application is substantially the same as the mechanism shown and described in Obergfell Patent #1,956,360, issued April 24, 1934, except for some changes which are shown in Figs. 2 and 3.

These mechanism changes permit the line connecting key ID to be manually operated at any time regardless of the position occupied by the switchhook operating member and is not operated by the replacement of the receiver on the cradle. The holding keys and 30 are locked 0 against manual operation when the receiver is resting on its cradle while after the receiver is removed both keys can be operated at will to open and close the holding circuits controlled thereby. In addition the replacement of the receiver on the cradle restores either or both holding keys.

Referring now to Figs. 2 and 3, key levers I0, 20, and extend through an opening in the subbase SB. The key levers ll], 20, and 30 are pivoted on shaft journalled in extension plates secured to the sub-base. A space bushing is provided on shaft between each of the keys I0, 20, and 30. The other end of the key levers are connected by pins 3|, 2|, and I2 to the link members 32, 22, and I3, respectively. The end of the link members 32, 22, and 3 are fork-shaped so that they move in and out on pins, such as pin 35, passed through the U-shaped portions of members 33, 4|, and I5 which serve as supports for insulated bushings, such as bushings 36 and IS. The members 33, 4|, and I5 are rotatable on a rod 34. As more clearly shown in Fig. 2, it will be seen that when the key lever 30 is moved downward and rotated on shaft II it imparts movement to the link 32 by means of pin 3|. Link 32 engages pin 35 in member 33 forcing member 33 to the right so that bushing 36 will engage and close springs 80. In a similar manner links 22 and I3 rotate members 4| and IE to cause the associated bushings to operate springs 8|, 82 and 83. Each of the key levers operates on a toggle principle, for instance, when key 30 is operated downward the pin 3| connecting the end of the key and link 32 assumes a position beyond a center line drawn between shafts II and 35 to hold the key in its operated position. Stop rod 66 serves as a stop for the normal position of the keys. The rod 65 serves as a stop for hold keys 36 and 20 in their operated positions while a bracket 46 mounted on plate 8 serves as a stop for line connecting key I6 in operated position.

Hold key levers 26 and 36 may only be operated when the receiver is off the cradle or switchhook and are automatically restored to normal position in response to the replacement of the receiver on the cradle. Referring to Fig. 2, rod 56 which is controlled by the receiver, is shown in position indicating that the receiver is resting on the cradle. Rod 56 bears on insulating washer 5| which is attached to the movable lever arm 52. Arm 52 is pivoted so that it is rotatable about the pin 53. A pair of fiat shaped lever arms 56 are secured together by means of pins 63, 6|, and 55. At the rear of the key unit the pin 55 is engaged by hook 54 formed in lever 52. A link member 66 is pivoted by pin 6| to the lever 56 and the opposite end is securely pivoted to the bearing pin 62 which is journalled in the extension plates of the sub-base. The end of link 66 is provided with a rod II provided with bushings I6 and I2 for operating springs, such as springs I5, 18, and I9. When lever 52 is moved downward it moves lever 56 upward by hook 54 engaging pin 55. This imparts a rotary motion to link 66 because it is pivoted at 62 and causes the plates 56 to be thrust forward or to the left as shown in Fig. 2. The rotation of link member 66 causes the bushings I6 and I2 to open springs I8 and I9.

The left end of plates 56 are held together by pin 63 in the release arm 64. The arm 64 is rotatable about shaft 34 so that the forward movement of levers 56 will pivot arm 64 about shaft 34 and pin 63 to cause the releasing rod 65, secured to arm 64, to press upon the top side of the link members 32 and 22. This downward motion of rod 65 restores keys 26' and 36 to their normal positions against stops 66. The rod 65 does not extend over to member I3 of key I6 and therefore the rod 65 does not restore key I6'as shown in the above mentioned Obergfell patent.

When the receiver or handset is removed from the cradle rod 56 moves upward and the levers 56 move to the right, as seen in Fig. 2, due to the spring tension of springs I5 which bear against bushings I6 and I2. This movement closes springs I8 and I9. Arm 56 in moving to the right raises the rod 65 so as to permit operation of keys 20 and 36. It will be noted that springs 86 and BI are non-locking and therefore with the receiver off the switchhook the holding circuits may be opened and closed at will. Further detailed description of the key mechanism and operation may be had by referring to the abovementioned Obergfell patent.

' Fig. 1 shows by means of the usual circuit diagrams a substation circuit S comprising a calling device CD, transmitter T, receiver R, induction coil 10, and the cradle springs CS shown in operated position with the handset removed from the cradle. The dotted line illustrates the subbase SB mounting the push-button PB, line connecting key I6, hold keys 26 and 36 and associated springs which the keys control. The ringer-bell RBI for line I and the ringer bell BB2 for line 2 are mounted in separate ringer-boxes terminating the two lines.

With the keys in normal position the substation circuit is normally connected to line I and therefore the subscriber need not operate any keys to originate or answer a call on line I. Key I6 may be operated either before or after the handset is removed from the cradle, thus making it possible for the subscriber to select the desired line before removing the handset. Assuming now that all the keys are in normal position then when the subscriber answers or originates a call by removing the handset the cradle springs CS close to connect the substation circuit S to line I as follows: from line I by way of conductors 96 and 92, normally closed springs controlled by springs 82 and 63 and thence by way of the heavy talking conductors and push button PB and cradle springs CS. Springs I8 and I9 in the subbase SB close in response to the removal of the handset to prepare points in the holding circuits for lines I and 2. Assuming now that the subscriber receives a call over line 2 while conversing over line I, such subscriber, after telling the party on line I to hold the connection, will operate hold key 36 thereby operating member 33 and bushing 36 to close springs 86 thereby completing a holding circuit for line I as follows: from conductor 96 of line I, the upper ringer coil .of RBI,v

conductor 9|, springs I9 and 86 to line conductor 92. The subscriber now operates the key I6 to its operated position to operate member I5 and bushings I6 to operate springs 83 and 82 to disconnect line I from the substation circuit and connect line 2 thereto. The substation S is now connected to line conductors 93 and 95 by way of the make contacts and springs 82 and 83. If desired the subscriber may hold this connection by operating hold key 26 thereby closing springs 8| to complete a holding circuit for line 2 as follows: from conductor 93, upper ringer coil of RBZ, conductor 94, springs I8 and 8| to conductor 95. In case conversation is terminated over line 2 the subscriber need not operate the hold key 26 or push button PB to release the connection on line 2 but operates the line connecting key I6 to disconnect from line 2 and return to line I. The impedance of the ringer coil in the holding bridge of line I is sufficiently high so that the subscriber can talk on the line even though the holding circuit is closed. However, it is not necessary to talk with the holding bridge on the line because the subscriber can remove the holding bridge by restoring key 36. After conversation the subscriber need not restore any of the operated keys since the hold keys 26 and 36 are automatically restored, if operated, in response to the replacement of the receiver and the forward thrust of arms 56 for operating rod 65 as previously described. The line connecting key I6 however remains in the position last operated by the subscriber since the replacement of the receiver does not in any way control its operation. The substation circuit may therefore be left connected to either line as desired dependent upon the position of the line connecting key I6, the hold keys may be operated at will only when the receiver is removed from the cradle to open and close the holding circuits, and such hold keys and holding circuits being automatically restored and opened in response to the replacement of the receiver.

Having described the invention, what is considered to be new and is desired to have protected by Letters Patent will be set forth in the following claims.

What is claimed is:

1. In a telephone system, a substation, a first and a second line terminating in said substation,

a holding circuit for each of said lines in said substation, holding means individual to each line for closing and opening said holding circuits, a supporting member in said substation, a receiver in said substation adapted to rest on said supporting member when not in use, means for rendering said holding means efiective for manual operation to open or close said holding circuits responsive to the receiver being removed from the supporting member, said last means restoring any operated holding means to open the corresponding holding circuit and for disabling said holding means against manual operation responsive to the receiver being replaced on said supporting member.

2. In a telephone system, a substation, a first and a second line terminating in said substation, a holding circuit for each of said lines in said substation, holding means individual to each line for closing and opening said holding circuits, a supporting member in said substation, a receiver in said substation adapted to rest on said supporting member when not in use, means for rendering said holding means effective for manual operation to open or close said holding circuits responsive to the receiver being removed from the supporting member, said last means restoring any operated holding means to open the corresponding holding circuits and for disabling said holding means against manual operation responsive to the receiver being replaced on said supporting member, a substation circuit in said substation, and line connecting means in said substation manually operable at will regardless of the position of said receiver and supporting member for connecting said substation circuit to either one of said lines.

3, In a telephone system, a substation, a first and a second line terminating in said substation, a holding circuit for each of said lines in said substation, holding means in said substation individual to each line and manually operable after removal of the substation receiver from the switchhook for completing or opening its individual holding circuit, and switchhook controlled means for preventing the operation of said holding means while the receiver is on the switchhook and for automatically restoring any operated holding means to open its individual holding circuit in response to the replacement of the receiver on the switchhook.

4. In a telephone system, a substation, a first and a second line terminating in said substation, a holding circuit for each of said lines in said substation, holding means in said substation individual to each line and manually operable after removal of the substation receiver from the switchhook for completing or opening its individual holding circuit, switchhook controlled means for preventing the operation of said holding means while the receiver is on the switchhook and for automatically restoring any operated holding means to open its individual holding circuit in response to the replacement of the receiver on the switchhook, and line connecting means in said substation operable independently of said switchhook controlled means for con necting either one of said lines to the talking circuit of said substation.

5. In a telephone system, a plurality of sets of springs, a substation circuit and a first and a second line terminating in said sets, a line connecting key for operating the first set of said springs to,connect either one of said lines to said substation circuit dependent upon the operated position of said line connecting key, a first holding key for operating the second set of springs, a holding circuit for said first line including said second set of springs, a second holding key for operating the third set of springs, a holding circuit for said second line including said third set of springs, an operating member having a plurality of positions, means controlled by said operating member in its first position for preventing the operating of said holding keys and the operation of their spring sets, said means controlled by said operating member in its second position for permitting manual operation of said holding keys and the operation of said corresponding spring sets to open and close said holding circuits at will, said line connecting key manually operable at any time regardless of the occupied position of said operating member to operate its corresponding spring set and connect either of said lines to said substation circuit, means for operating said operating member from its second position to its first position, said first means operated responsive thereto for restoring only said holding keys and their corresponding spring sets to open the holding circuits without restoring the line connecting key and its corresponding spring set.

JOHN H. VOSS. 

